Characterization of tobacco expressing functional oat phytochrome. Domains responsible for the rapid degradation of Pfr are conserved between monocots and dicots

Journal Article · Mon Jul 01 00:00:00 EDT 1991 · Plant Physiology; (United States)

DOI:https://doi.org/10.1104/pp.96.3.775· OSTI ID:5699495

Cherry, J R; Vierstra, R D ^[1]; Hershey, H P ^[2]

---

1. Univ. of Wisconsin, Madison (United States)
2. E.I.du Pont de Nemours and Co., Wilmington, DE (United States)

Constitutive expression of a chimeric oat phytochrome gene in tobacco (Nicotiana tabacum) results in the accumulation of a functional 124-kilodalton photoreceptor that markedly alters the phenotype of light-grown tobacco. Here, we provide a detailed phenotypic and biochemical characterization of homozygous tobacco expressing high levels of oat phytochrome. Phenotypic changes include a substantial inhibition of stem elongation, decreased apical dominance, increased leaf chlorophyll content, and delayed leaf senescence. Oat phytochrome synthesized in tobacco is indistinguishable from that present in etiolated oats, having photoreversible difference spectrum maxima at 665 and 730 nanometers, exhibiting negligible dark reversion of phytochrome - far red-absorbing from (Pfr) to phytochrome - red-absorbing form (Pr), and existing as a dimer with an apparent size of approximately 300 kilodaltons. Heterodimers between the oat and tobacco chromoproteins were detected. Endogenous tobacco phytochrome and transgenically expressed oat phytochrome are rapidly degraded in vivo upon photoconversion of Pr to Pfr. Breakdown of both oat and tobacco Pfr is associated with the accumulation of ubiquitin-phytochrome conjugates, suggesting that degradation occurs via the ubiquitin-dependent proteolytic pathway. This result indicates that the factors responsible for selective recognition of Pfr by the ubiquitin pathway are conserved between monocot and dicot phytochromes. More broadly, it demonstrates that the domains(s) within a plant protein responsible for its selective breakdown can be recognized by the degradation machinery of heterologous species.

• DOE Contract Number: FG02-88ER13968
• OSTI ID: 5699495
• Journal Information: Plant Physiology; (United States), Journal Name: Plant Physiology; (United States) Vol. 96:3; ISSN 0032-0889; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
BIOTECHNOLOGY
CEREALS
CHEMICAL REACTIONS
GENES
GENETIC ENGINEERING
GRAMINEAE
GROWTH
LILIOPSIDA
MAGNOLIOPHYTA
MOLECULAR BIOLOGY
OATS
ORGANIC COMPOUNDS
PHENOTYPE
PHOTOCHEMICAL REACTIONS
PHYTOCHROMES
PIGMENTS
PLANT GROWTH
PLANT STEMS
PLANTS
PROTEINS
TOBACCO